Dynamically inserting javascript into HTML that uses document.write

In general, script tags aren't executed when using innerHTML. In your case, this is good, because the document.write call would wipe out everything that's already in the page. However, that leaves you without whatever HTML document.write was supposed to add.

jQuery's HTML manipulation methods will execute scripts in HTML for you, the trick is then capturing the calls to document.write and getting the HTML in the proper place. If it's simple enough, then something like this will do:

var content = '';
document.write = function(s) {
    content += s;
};
// execute the script
$('#foo').html(markupWithScriptInIt);
$('#foo .whereverTheDocumentWriteContentGoes').html(content);

It gets complicated though. If the script is on another domain, it will be loaded asynchronously, so you'll have to wait until it's done to get the content. Also, what if it just writes the HTML into the middle of the fragment without a wrapper element that you can easily select? writeCapture.js (full disclosure: I wrote it) handles all of these problems. I'd recommend just using it, but at the very least you can look at the code to see how it handles everything.

EDIT: Here is a page demonstrating what sounds like the effect you want.


I created a simple test page that illustrates the problem:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
    <head>
        <meta http-equiv="Content-type" content="text/html; charset=utf-8" />
        <title>Document Write Testcase</title>
    </head>
    <body>
        <div id="container">
        </div>
        <div id="container2">
        </div>

        <script>
            // This doesn't work!
            var container = document.getElementById('container');
            container.innerHTML = "<script type='text/javascript'>alert('foo');document.write('bar');<\/script>";

            // This does!
            var container2 = document.getElementById('container2');
            var script = document.createElement("script");
            script.type = 'text/javascript';
            script.innerHTML = "alert('bar');document.write('foo');";
            container.appendChild(script);
        </script>
    </body>
</html>

This page alerts 'bar' and prints 'foo', while I expected it to also alert 'foo' and print 'bar'. But, unfortunately, since the script tag is part of a larger HTML page, I cannot single out that tag and append it like the example above. Well, I can, but that would require scanning innerHTML content for script tags, and replacing them in the string by placeholders, and then inserting them using the DOM. Sounds not that trivial.

Tags:

Javascript

Html

Ajax

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